This photograph inspired me to create my GIMP plug-in Colour Cast Reduction1…
It was based on an idea proposed by Krikor and coded by Tim Tran in the GimpLearn forum.
As noted by Terry and satimis, the GIMP auto-levels or auto-equalize can be helpful but produce excessive contrast. GIMP Auto/Stretch Contrast can be very useful when the image is excessively dark, light, or lacks contrast. Unfortunately it is not available in Gimp Python, so I had to devise a way of achieving a similar result.
The plug-in creates a contrast layer with an opacity of 10% to compensate for the common loss of contrast in faded photographs, but a better adjustment can be made with the base layer.
col-cast-reduction1.zip (3.1 KB)
As with any automatic means of colour-cast reduction, it uses the assumption that the image should average to neutral. Try it on a sunset or a candlelit scene and the results are likely to be very peculiar!
The result with this image with no further adjustment.
